In this paper, a computer-aided system for orbital prosthesis rehabilitation is introduced. With the system, a 3D model of the orbital prosthesis can be easily reconstructed from the CT image of a patient by referring to the normal eye of the patient, and the rehabilitation result by the model can be simulated before the surgery. This facilitates surgeons to design appropriate orbital prosthesis and improve rehabilitation esthetics. Based on the system, the preoperative surgery planning for orbital implant can also be made. This improves the reliability, safety and intuition of the rehabilitation surgery well. The system has been applied to clinical CT images of patients, and the experimental results show effectiveness and acceptability of the system in the clinic.